Rising oil prices and the finite nature of fossil fuels have led to an increased demand for alternative fuel sources. One feasible and renewable option is the conversion of biomass material into biofuel. Typically, the conversion process involves the flow of the biomass material through a series of chemical, thermal, and mechanical treatments. Currently, however, generating the flow of the biomass material through the series of treatments is difficult and expensive. Often, significant amounts of auxiliary materials and energy are required to generate the flow of the biomass material through the series of treatments. In order to maximize the efficiency of the conveyance of the biomass material through the series of treatments, and hence reduce the overall cost of generating the biomass flow, the proper design of the industrial processes and equipment is imperative. In order to properly design the industrial processes and equipment, the accurate measurement of the rheological properties of the flow of the biomass material through the series of treatments is necessary.
The most important rheological parameter in the design of industrial processes and equipment is yield stress. Yield stress is the amount of stress that must be exceeded in order to make a structured fluid flow. There are numerous methods for measuring yield stress, ranging from simple practical methods to techniques employing sophisticated rheometers. The most appropriate method can vary from one material to another, as well as, one application to another. Yield stress measurements for biomass material suffer from a number of instrument and material related difficulties, including wall slip, sample ejection, stresses exceeding sensor capacity and sample separation into multiple phases. Measurements are often made using a vane geometry, but this approach is limited to low solids concentrations. Torque rheometry can be used at higher solid concentrations, but this technique can be quite slow (approximately 1.5 hours for a single measurement). Further, both of these approaches utilize apparatuses that are quite expensive, with costs in the range of $50,000-$100,000.
Therefore, it is a primary object and feature of present invention to provide a device and a method for measuring the rheological properties of a yield stress fluid, such as a biomass material, and/or for measuring the rheological properties of other non-Newtonian fluids requiring high stress or special handling.
Therefore, it is a further object and feature of present invention to provide a device and a method for measuring the rheological properties of a yield stress fluid that are simple to operate and inexpensive to manufacture.
Therefore, it is a still further object and feature of present invention to provide a device and a method for measuring the rheological properties of a yield stress fluid that allow a user to quickly receive the results of such measurements.
In accordance with the present invention, a device is provided for measuring a rheological property of a fluid. The device includes an auger having a shaft extending along an axis and a helical flange extending radially about the shaft. The auger is movable in the fluid between a first position and a second position. A sensor is operatively connected to the auger. The sensor measures a force on the auger as the auger moves from the first position to the second position.
A container defines a cavity for receiving the fluid therein. It is contemplated for the sensor to be load cell. The first position and the second position are axially spaced. A positioning structure may operatively connected to the auger. The positioning structure moves the auger between the first and second positions. The positioning structure includes a motor and linkage operatively connecting the motor to the auger. The sensor interconnects the linkage and the auger. A guide structure guides movement of the linkage as the auger is moved between the first and the second positions.
In accordance with a further aspect of the present invention, a device is provided for measuring a rheological property of a fluid. The device includes a container for receiving the fluid therein and an auger. The auger has a shaft extending along an axis and a helical flange extending radially about the shaft. The auger is movable in the fluid between a first position and a second position. A sensor is operatively connected to the auger. The sensor measures a force on the auger as the auger moves from the first position to the second position. Linkage is interconnected to the sensor. The linkage translates motion to the auger.
The sensor may be a load cell and the first position and the second position are axially spaced. A motor is operatively connected to the linkage for imparting axial movement thereon. A guide structure guides movement of the linkage as the auger is moved between the first and the second positions. The auger is releasably connected to the sensor.
In accordance with a still further aspect of the present invention, a method of measuring a rheological property of a fluid is provided. The method includes the steps of threading an auger into a portion of the fluid and interconnecting the auger to a sensor. The sensor generates a signal corresponding to the rheological property of the fluid. The auger is moved in a predetermined direction so as to generate the signal.
The auger has a shaft extending along an axis and a helical flange extending radially about the shaft. The sensor may be a load cell. The step of moving the auger in the predetermined direction includes the step of moving the auger axially between a first position and the second position. Movement of the auger is guided between the first and second positions and the auger is releasably connected to the sensor.